1. Field of the Invention
The present invention relates to a hand guided vibrating roller for compacting the ground by vibrating a pair of roller wheels provided at the front and rear of a body.
2. Description of Related Art
Vibrating rollers are compacting machines with roller wheels that are vibrated by a vibration generating apparatus provided at the inside of the roller wheel or the body to apply a vibratory force together with its weight to enhance the compacting effects. Hand guided vibrating rollers are comparatively small and lightweight among the vibrating rollers and non ride-on type machines. The operating performance of the hand guided vibrating roller is superior in the initial compaction of the asphalt pavement, the compaction of the shoulder of a road, a sidewalk, a narrow alley and others, so that the hand guided vibrating roller is widely used in the municipal road maintenance and the environmental maintenance.
FIG. 1 shows a conventional hand guided vibrating roller 90. The hand guided vibrating roller 90 comprises an engine 91, a machine 92 mounting a hydraulic pump (not shown) and others, a front roller wheel 93A and a rear roller wheel 93B arranged in parallel to support the machine 92, a hydraulic motor (not shown) for transmitting a driving force to the front roller wheel 93A and the rear roller wheel 93B by a pressure oil from the hydraulic pump, and a steering rod 95 connected to a rear end of the machine 92 over a connecting bracket 94.
The hand guided vibrating roller 90 travels in the area to be compacted with the roller wheels 93A, 93B vibrating. When the direction needs to be changed (hereinafter called steering n) during operation, a worker pushes or pulls the steering rod 95 to the left or the right to face the whole hand guided vibrating roller to the desired direction.
The hand guided vibrating roller 90 masses 500 kg to 1000 kg. In the case of the steering, the worker holds the steering rod 95 with both hands and operates it with all his strength, which can only be handled by a skillful worker and which requires a lot of labor. In order to reduce the force required in the steering, the steering rod 95 is made longer to make the turning force smaller; however, the required force is still large.
Further, if the steering rod 95 is made longer, because the steering rod 95 cannot be controlled in the compaction of the narrow road and narrow ditch, the steering cannot be performed.
Furthermore, during the compacting operation, the worker needs to move on the compacted area right after the compaction while holding the steering rod 95, which may lower the quality of the compacted area.
It is an object of the present invention to provide a hand guided vibrating roller which does not require a large force and which does not require complicated operations and which can easily perform the steering in a small space.
In order to achieve the above object, a hand guided vibrating roller of the present invention, which comprises a pair of front and rear roller wheels provided in parallel, a machine supported by the pair of the front and rear roller wheels, a hydraulic pump mounted on the machine, a hydraulic motor for driving the roller wheels, provided inside the roller wheels, and a steering rod elongating from the rear portion of the machine, comprises a supporting frame freely rotated around a vertical axis, supporting at least one of the roller wheels, and an actuator for rotating the supporting frame.
Accordingly, the roller wheel can be rotated through the supporting frame by an actuator, so that the steering is not hand-operated and the fatigues due to the steering can be relieved and further the safety can be improved.
Here, a hydraulic cylinder may be used as the actuator. In this case, the supporting frame can readily be rotated by the expansion and the contraction of a cylinder rod of the hydraulic cylinder.
Further, the hand guided vibrating roller of the present invention may comprise a pressure oil supplying means connected to the hydraulic cylinder with a hydraulic hose having a directional control valve, and a directional control valve operating means for switching the directional control valve provided at a drive operating unit attached to the steering rod.
Here, the drive operating unit is a part for making the hand guided vibrating roller travel forward and backward, terminate, and perform the steering.
Further, it is preferable to use a solenoid directional control valve (herein after called a solenoid switching valve) as the directional control valve; however, the hand-operated directional control valve (herein after called a hand-operated switching valve) can be used.
Accordingly, the hydraulic cylinder is connected to the pressure supplying means with the hydraulic hose having the directional control valve, and the directional control valve operating means is integrated with the drive operating unit attached to the steering rod, so that the hand guided vibrating roller is superior in the operating performance.
Further, in the hand guided vibrating roller of the present invention, the directional control valve may be a solenoid directional control valve, and a solenoid directional control valve operating means for switching the solenoid directional control valve is provided at a forward-backward movement lever attached to the drive operating unit. The operating performance of the hand guided vibrating roller can be improved.
Furthermore, the hand guided vibrating roller of the present invention further comprises an automatic roller wheel neutralizing apparatus including a rotating position detecting means for detecting the rotating position of the roller wheel rotated in one direction around a vertical axis, and a neutral position restoring means for restoring the roller wheel to the straight forward traveling state by rotating the roller wheel in the direction opposite to the current rotating direction based on the rotating position detected by the rotating position detecting means.
Accordingly, when at least one of the roller wheels is rotated in one direction, clockwise or counterclockwise, the roller wheel of the hand guided vibrating roller can automatically be made in the straight forward traveling state by operating the automatic roller wheel neutralizing apparatus without the complicated operations.
Further, in the hand guide vibrating roller of the present invention, the supporting frame is rotatively supported by a slewing rim bearing provided right above the roller wheel, and the hydraulic pump and the hydraulic motor for driving the roller wheel are jointed by hydraulic hoses inserted into a hollow portion of the slewing rim bearing.
Accordingly, since the supporting frame is rotatively supported by a slewing rim bearing provided right above the roller wheel, the hydraulic hoses connected the hydraulic pump with the hydraulic motor for driving the roller wheel can be inserted through the hollow portion formed at the circumference of the center of pivot of the slewing rim bearing, so that the hydraulic hoses can be piped efficiently. Therefore, the damage of the hydraulic hoses caused by the dynamic bending and tension of the hydraulic hoses due to the rotation of the supporting frame can be prevented. As a result, the durability and reliability of the hydraulic hoses can be improved.
In the hand guide vibrating roller of the present invention, a fixing member having a through hole for the hydraulic hoses may be fitted in the hollow portion of the slewing rim bearing.
Here, the through holes for the hydraulic hoses can be any number and any shape unless they hold the movement of the hydraulic hoses. Further, the material of the fixing member is not limited but it is preferably made of rubber or synthetic resin.
Accordingly, the fixing member for the hydraulic hoses is fitted in the hollow portion, and the hydraulic hoses are inserted into the through holes. Then, the movement of the hydraulic hoses can be held. Therefore, the hydraulic hoses can be prevented from touching the inner face of the slewing rim bearing, which protects the hydraulic hoses.